Method of and apparatus for welding



, Nov. 7, 1944. Q M MacCHEsNEY ET AL 2,362,388

METHOD OF AND APPARATUS FOR WELDING Filed Sept. 19, 1941 5 Sheets-Sheetl N0V- 7 1944. c. M. MaccHEsNEY ET AL 2,362,388

METHOD OF AND APPARATUS FOR WELDING Filed Sept. 19, 1941 v INVENTORS.CeSzeP M Mac Chesney )fa/065er A ORNEYS.

Nov. 7, 1944. c, M MacCHEsNEY ET AL 2,362,388

METHOD QF AND APPARATUS FDR WELDING Filed sept. 19, 1941 5 sheetsheet sRJ v 0 Dmxw Nov. 7, 1944. c. M. MaccHEsNEY ET AL 2,352,388'

METHOD OF'AND APPARATUS FOR WELDING Filed sept. 19, 1941 5 Sheets-Shea?I4 1N VEN TORS.

Nov. 7, 1944.

c. M. MaccHEsNEY ETAL METHOD 0F AND APPARATUS FOR WELDING Filed sept,19, 1941 5 Sheets-Sheet 5 1N VENTORS.

C/ may 5 I ceder' AORNEYS.

Patented Nov. 7, 1944 UNITED STATES PATENT oFFlcE METHOD or ANDAPPARATUS Fon WELDING I Chester M. MacChesney and William Schroeder,Chicago, lll., assignors to Acme Steel Company, Chicago, lll., acorporation oi' Illinoisp Application september 19, 1941, serial No.411,474

(c1. 21a- 4 i 19 Claims.

' separate strips so that a very great length of strip material may beformed to be wound in a coil or otherwise used. It has heretofore beenthe usual practice to unite the ends of two such strips by butt weldsbut this method has proved unsatisfactory because the tensile strengthof the composite strip at the joint does not consistently approach thestrength of the body portions of the strips which are thus united. Thesewelding operations are carried on at temperatures of approximately 2500Fahrenheit, which exceeds the melting point of the metal so that themetal melts and flows during the welding operation, but a complete andsatisfactory union of the metal of the two strips has not been attainedby this practice, due in part to the fact that it is necessary. to gripthe ends of the m'etal strips in proximity to the place where they abutagainst each other so that the gripping devices cool the metal close tothe joint and cause narrow zones predetermined extent the ends of thestrips to be connected, thenheating them by the passage of an electriccurrent therethrough; and then uniting them by a forging operation. v Afurther object is to provide means for causing the ends of the strips tohave a wiping action upon each other when they are brought into theoverlapping relationship, thereby insuring a,good contact between themetal strips before they are Another object of the invention is toprovide means for effecting a pre-A heated and forged.

determined heating of the overlapping strip ends by the passage of ameasured electric current therethrough prior to the forging or weldingstep. A further object is to provide improved' clamping means forholding the ends of the metal strips and effecting a relative movementthereof to bring them into overlapping relationship. Still another'object is to provide a stop for accurately positioning the ends 0f thestrips to be united in combination with clamping means for holding thestrip ends and means for withof weakness to be produced on oppositesides of and close to the joint, in which zones subsequent failureusually occurs.

The principal object of the present invention is to overcome theabove-mentioned diillculties,

`and others, by providing an improved method of procedure according towhichthe ends of the strips are overlapped and united by a forgingoperation with the metal of the strip ends heated only to a forging orplastic heat, that is, to a temperature of approximately 20 0 F. Duringdrawing the stop and eifecting a relative movement of the clamping meansto bring the strip ends into a definite or predetermined `overlap- 'pingrelationship. Another object is yto provide improved fluid operated-mechanism for actuating the dies by which the foregoing operation iseil'ected. Other objects relate to various features of construction andarrangement which will appear more fully hereinafter.

The nature of the invention will be understood from the followingspecication taken with the accompanying drawings in whichone embodithisoperation the strips may be ripped or held at substantial distances fromth` r extremities so that the heat produced by welding may be graduallydissipated through a considerable length of strip material without theobjectionable cooling of the strip close to the joint which ischaracteristic of butt welding operations. A further object ofgtheinvention is to provide an improved method and an improved appara-` tusfor forming a welded joint of a strength ap-j proximating that of themetal strips which are united and having substantially the same widthand thickness. Still another object of the inv vention is to providemeans for overlapping to a ment of the improved apparatus and oneexample of theimproved method are illustrated. InA

the drawings,

Figure 1 shows a partial front elevation of the improved weldingmachine, the supporting frame or standard and the electric circuitconnections being removed;

Fig. 2 shows a perspective view of the two strip ends during theoperation of eilecting a relative movement thereof .to bring them'intooverlapping relationship;

Fig. 3 is a perspectiveyiew of the strip ends shown in Fig. 2 after theyhave been overlapped;

Fig. 4 is a perspective view of the strip en'ds illustrated in Fig. 3after they have been united by the lap forge welding operation of thepresent invention;

Fig. 5 is a horizontal section taken on the line 5 5 of Fig. 1 and 5-5of Fig. 6;

Fig. 6 shows a vertical section taken on the line 6-6 `of Fig. 1;

Fig 'l shows a vertical section taken on the line 'l-l of Fig. 5;

Fig. 8 shows a side elevation of the foot lever mechanism by which theclamping device shown in Fig'. 6 is operated;

Fig. 9 shows a vertical section taken on the lineA 9 9 of Fig. 1;

Fig. 10 is a detailed section taken on the line itl- I0 of Fig. l;

Fig. 11 shows a partial side elevation ofthe foot lever mechanism foroperating the clamping device illustrated in Fig. 9;

Fig. 12 'shows a somewhat diagrammatic front elevation of a portion ofthe apparatus illustrated in Fig. l, showing the two strip ends beingpositioned against the Opposite sides ofthe removable stop;

Fig. 13 is a side elevationof the two strip ends illustrating on anenlarged scale the relative movement of these strip ends during theoperation of bringing them into overlapping relation- Ship;

Fig. 14 is an enlarged front elevation of a portion of the weldingapparatus showing the clamps for holding the strip ends and the weldingdies in their retracted positions preliminary to uniting the strip endsby a forging' action;

Fig. 15 is a partial front elevation similar to that of Fig. 14, showingthe welding dies after they have been rocked together to effect thewelding of the overlapping strip ends, as illustrated in Fig. ll;

Fig. 16 is a sectional view taken on the line iti-i6 of Fig. 15; and

Fig. i7 is a diagrammatic view of the electric circuit connections ofthe system for causing a predeterminedcr xed amount of electrical energyto pass through the overlapping portions of the metal strips preliminaryto each forging operation.

As illustrated in the drawings, the improved welding apparatus comprisesa horizontal supporting plate 2B which may be mounted upon legs orpedestals to act as a table for carrying the various parts of theapparatus. This plate is provided at its forward edge with a notch 2liiin which a part of the welding mechanism is l0- cated, and it carriesavertically extending double-walled frame or plate 2l having laterallyextending iianges 2la which are bolted or otherwise secured to the topsurface of the horizontal plate 20. as shown particularly in Figs. 6 and9, the lower part of the plate 2l extending downwardly through the notch20". These supporting plates carry a pair of clamping blocks 22 and 23,shown particularly in Fig. 1, which are adapted to cooperate with theclamping members 24 and 25, respectively, to hold the strip ends 26 and2Gb which are to be united by the welding operation. When thesestripends 26l and 25b are initially placed in the machine on theclamping blocks 22 and 23, they are located by positioning their endsagainst a removable gauge or stop member 2l, as shown in Fig. 12. Theclamping members 24 and 25 are then mathe blocks 22 and 23,respectively, whereupon the gauge member 21 is withdrawn and the block23 and clamping member 25 are moved through an arc 28, as shown in Fig.13, so that the strip end 2Gb is carried upwardly and over the strip end26 and eventually brought down against the end 26 with a reverse motionand a wiping action, as indicated by the arrows on the arc 28. The pathof travel of the strip end 26 is such nipulated to hold the strip endssecurely against that it depresses the end 26* as the end of themovement is reached so that a close contact and a deilnite overlappingrelationship is brought about between the strip ends and they are causedto exert a resilient pressure on each other preliminary to the weldingoperation.

With the strip ends held in the overlapping relationship illustrated byfull lines in Figs. 13 and 14, and with a substantial length of stripmaterial between the clamping means, anvelectric current is then passedthrough the strip ends to heat'them to the desired forging temperature,determined automatically as hereinafter described, and the welding dies28 and 3U are then actuated to form a welded joint 3| having thecharacteristics illustrated in Fig. 4, where it will be seen that thematerial at the joint is of substantially the same width and thicknessas other parts of the strip removed from the joint. To accomplish this,the lower die 29 is provided with a rectangular groove 29 of the samewidth as the strip ends which are received Within it and the upper die30 is provided with a corresponding rectangular projection 3D", as shownin Figs. 14, 15 and 16. The projection 30* is adapted to enter andsubstantially fit the recess 29a but the depth oi' the projection isless than the depth of the recess, leaving a space which correspondssubstantially to the thickness of the strip 26. When the two weldingdies are brought together, as shown in Figs. l5 and 16. their end facesabut against each other and the projection 30 enters the recess 29 toeffect the welding of the v overlapping strip ends and determine thethickness and width of the joint. inasmuch as the overlapping ends areconilned during this welding and forging operation, there is an endwiseflow of the metal to permit it to accommodate itself to the conllnes ofthe space between the lower part of the recess 29xi and the projection30a. This endwise Ilow of the metal might be compensated for bypermitting the simultaneous relative separation of the blocks 22 and 23and their clamps 24 and 25 but, if these parts remain relativelystationary, the slight wrinkled eiect which may be produced in the stripmaterial adjacent the joint will ordinarily be found unobjectionable.

Withthe foregoing explanation of the general mode of operation oi theapparatus, reference will now be had to the method of mounting andactuating the clamping devices. The clamping block 22 which carries thestrip end 2Sl is mounted directly upon a bracket 32 and the clampingblock 23 is mounted, through the agency of intermediate parts, uponanother bracket 33. rFliese brackets comprise horizontally extendingparts 32a and 33, upon which the clamping devices are mounted, andvertically extending ilanges 33b and 33b which are secured to the sidewalls 2|b of the upright frame 2|. The flange 32b is provided withelongated slots 32c engaged by studs 34 which enter threaded aperturesin one of the side walls 2|3 of the vertical frame, and thisconstruction permits the bracket 32 to be adjusted vertically to permitthe apparatus to accommodate different thicknesses of strips. Thehorizontal portion 32 of the bracket is supported in all of thesevertical positions by an adjusting screw 35 which threadedly engages anaperture in the base plate 20 and which is held in adjusted position bya lock nut 36, as shown in Fig. 1. Similarly, the ange 33b of `the othersupporting bracket 33 is provided with elongated slots 33 which areengaged by studs Yacontece commodate different thicknesses ot stripmaterial. The bracket 33 is supported in a similar manner -by a setscrew 39 which engages a threaded aperture in the plate 20, being heldin adjusted position by a lock nut 40. Inasmuch as the two clampingblocks 22 and 23 are to be connected in the electric circuit by which acurrent is passed through the strip ends which are to be weldedtogether, it isnecessary to insulate the supports for these blocks fromeach other and this is accomplished by means of sheets of insulatingmaterial 4| winch are interposed between the flange 33b and the adjacentface of the frame 2l and also between the ange 33b and the heads of thestuds 38. Insulating busliings 42 are mounted in the slots 33c aroundthese Studs so that the bracket a3 is thus insuiated from its support.To complete this insulation, an insert 43 of insulating material ismounted in a recess in the bottom of the horizontal portion 33a of thebracket 33 for Iengagement; by the supporting stud 39. The electricwelding circuit is connected directly. to the clamping blocks 22 and 23.For this purpose, the secondary winding of the transformerv included inthe welding circuit, as hereinafter described, is connected to laminatedbars 44 which are attached to the end faces of the blocks 22 and 23 bymeans of plates 45 and studs 46.

bers are secured in adjusted position by lock nuts 56. When the stripends are positioned against The horizontal portion 32a of the bracket 32has a longitudinally extending groove 32d formed in its upper side andadapted to be tted by a corresponding projection or rl'b Reformed on'the underside of the clamping block 22. The .lower part of the clampingblockis provided withanelongated slot 22d adapted to receive a bolt orstud 41 which extends upwardly into an opening 22e ormed'in the lowerpart of the block 22. A washer 48 and a nut 49 engage the threaded upperportion oi'` this stud for clamping the-block 22 in adjusted position onthe bracket 32. By this arrangement the Iblock 22 may be adjustedlongitudinally to' ward and from the gauge or stop member 21 .pre-

viously referred to. 'Ilhe other clamping block 23 is carried byvanintermediate member 50 which is similarly provided on its underside witha downwardly extending rib or projection 50*aL arrangedto enter a grooveor keyway 33d formed` in the upper side of the horizontal portion 33 ofthe other supporting bracket. A bolt or stud 5I ex-V tends upwardly fromthe bracket 33 through an elongated slot 5l!b which is formed in theintermediate member 50 and the threaded portion of the bolt or stud '5|is engaged by a; washer 52 and a. nut 53 which permit the intermediatemember 50 to have a longitudinal adjustment on the bracket 33 forthepurpose of bringing about a corresponding adjustment of the clampingblock 23 similar to the previously described adjustment of the block 22.y

The clamping blocks 22and 23 are provided along their rear edges withupwardly extending shoulders 22f and 231', respectively, and tleseshoulders are enlarged at spaced intervals to form the bosses 22K and232. These bosses arel provided with threaded apertures Ain, which .aremounted adjusting screws 55 shown in Flgs. 1 and 5, which act aspositioning members against which the lateral edges of the strip `ends26 and 26h are adapted to be positioned when they are placed in themachine. These positioning memobtained, the foot pedal 10 may bereleased and.

the members 55, with their ends engaging the gauge member 21, they aresecured in those positions by moving the clamping members 24 and 25downwardly to grip them on their upper sides.

As shown particularly in Figs. 1 and 10, the clamping member 24 isprovided with a rectangular aperture 24 formed in theI upwardlyprojecting body portion 24b thereof, and this aperture is adapted toreceive' the end of a lever 53 which is pivotally connected to theclamping a lever 62 having mounted on the free end there- Y of a plug62, formed of hard rubber or the like. which is adapted to engage theupper side vof the clampingmember. As shown in Figs. 5 and 9, the lever62'is pivotally mounted upon a shaft 63 which is secured in the sideframe members of the upright frame 2|, the lever 62 being providedwithla hub portion B2b at the point where it is pivotally mounted on theshaft. A ,collar 64 is secured on the end of `the shaft to hold thelever 62 in position thereon. The rear end of the lever extends betweena pair of ears 65"I formed on the upper'end of a coupling member N65having a threaded connection at its lower end with a connecting rod 66,the rod being secured I'he rod 66 extends downwardly and is pivot-'-ally connected through a coupling member 68 with a foot pedal 1U. Thisfoot pedal is pivoted at the point 1| upon a `supporting pedestal 12which is located on the floor or other support by which the frame of themachine is carried. The foot Apedal 10 has a plate 10 adapted to beengaged by the foot of the operator and adjacent this plate there ismounted an upwardly extending ratchet member 13 having a rhandle 13* atits upper end. This ratchet member is pivoted at 14 upon a bracket 15secured to the :door or other support and a coil spring 16 normallyforces the ratchet member 13 toward the left, as shown in Fig. 1l, sothat fonel of its teeth will engage the edge of the plate 10e to holdthe foot pedal 10 in adjusted position. B y means of this arrangement,the operator may press downwardly on the foot pedal to actuate the lever62 which will then force .the clamping member 24 downwardly against theclamping block 22 which is seated on the bracket 32. When the desiredpressure is the ratchet member 13 will then hold the clamping member 24in the desired position.

The other clamping member 25 is similarly provided with a rectangularaperture 25 in the bpdy portion 25b thereof and this aperture yreceivesthe forward end of an operating lever 11 whichis pivoted thereto by apin 18. The lever 11, which isoi' bell crank form, is pivoted by (a pin19 between two ears 23h which are formed on the block 23. A coil springis mounted on a flange 231, extending rearwardly from the block 23. andit engages the lever" to cause the clamping member 25 to move norisjournaled in the previously described ears 23h carried by the block 23and also in another ear 231 which extends rearwardly from this block, asshown in Fig. 5, and this shaft has mounted on it between the ears 23h acam 85 which is adapted to bear against the plunger 8|. An operatinghandle 8S is secured upon the other end of the shaft 84, as illustratedin Figs. l and 5, and upon turning this handle the cam 85 may beutilized to rock the lever 11 about its pivot and thereby force theclamping member 25 downwardly until it grips the strip end 25b with ayielding pressure arising from the presence of the spring 83 in theconnection between the cam and the clamping member. By this arrangement,the strip end 26h may be gripped between the block 23 and the clampingmember 25 with sufficient pressure to hold it while the block '23 isbeing moved through the oscillatory path illustrated by the arc 23 in`Fig. 13 for the purpose of bringing the strip ends into a substantiallydefinite or predetermined overlapping relation with each other.

After that overlapping relation has been brought about, the clampingImember 25 may be caused to engage the strip end with the pressurerequired during the welding operation by actuating a lever 81 which ismounted on the shaft 53 by which the corresponding lever 52 is carried.rThe lever 31 has an enlarged hub portion 81b engaged by a collar 89which retains the lever in place on the shaft and the forward free endof the lever is provided with a pad 812- of hard rubber or the likewhich is adapted to engage the upper side of the clamping member 25 andwhich serves to maintain the electrically insulated condition of theparts which grip the strip end 2Gb. r1Ehe other end of the lever 81 ispivoted at 90 to a connecting member 9| which is threadedly engaged by arod 92 adapted to be held in adjusted position ytherein by a lock nut93. The rod 92 extends downwardly and is pivotally connected at thepoint S5 to a foot pedal 96 similar to the foot pedal 1t previouslydescribed. This foot pedal is pivoted at the point 91 on a pedestal 98extending upwardly from the floor, and the free end of this foot pedalcarries a plate 96a adapted to be engaged by the foot of the operatorand having an edge which is adapted to interlock with the teeth of therack bar 99 provided with a. handle 99e. A coil spring |00 normallymaintains the teeth of the rack bar in engagement with the plate 95a anda pin |01 establishes a pivotal connection between the rack bar-and thebracket |02 mounted on the floor. By swinging the rack bar 99 away fromthe plate 96B, the foot pedal is y released to permit lthe operator to`actuate the lever 81 and thereby =Dress the forward end of the leverdownwardly against the clamping member 25. The rack bar 99 may then becaused to lock the pedal in this position so that the clamping memberwill be firmly held during the welding operation. Y

As heretofore indicated, it is necessary to impart to the block 23, andparts carried thereby,

a motion through the arc 28 illustrated in Fig. 13 in order to bring thestrip ends into overlapping relationship and, for this purpose, theblock 23 is mounted for relative movement with respect to theintermediate member which is secured on the bracket 33. To permit thisrelative movement, the end of the block 23' which is farther away fromthe welding dies is supported from the member 50 by a pair of links |05which are pivotally connected to the members 23 and 50 by pins |06.Adjacent its other end, the block 23 is provided with a downwardlyextending projection 23k, shown in Figs. l and '1, which projectsbetween a pair of iianges 50V formed on the member 50. A shaft |01 isjournaled in the forward flange 5Uc and in a bushing |08 mounted in theother ilange, and a hand wheel |09 is secured to the forward end of thisshaft to permit it to be turned by the operator. rihe portion of .theshaft |01 between its bearings is formedv as an eccentric |012L which isjournaled in an aperture formed in the depending portion 23k of theblock 23, so that when the hand wheel |09 is turned the eccentricportion |01a will cause the block 23 to move the strip end 2Gb throughthe arcuate path shown in Fig. 13. When the block 23 is in its normalposition, as shown in Fig. l, the angu, lar position of the shaft |01 isfixed by the en-f gagement of a lug |096-, formed on the handle,` with alug 50i which projects downwardly from.

the member 58. After the shaft |01 has been turned through the necessaryarc to move the strip end 2Bb through the arcuate path shown in Fig. 13,the limiting angular position of the shaft |01 is determined by a stopscrew ||0 which threadedly. engages the lug 50d and which is held L inadjusted position by a lock nut By adjusting the screw H0, the extent ofangular-'I movement of the shaft |01 and its eccentric portion |01a maybe regulated to cause the overlapping of the strip ends to take place inthe desired manner. After the strip ends have been overlapped with theclamping member 25 held in its clamping position by the cam 85, the footpedal 96 is operated to cause the lever 81 to hold the clamping member25 securely in place while the welding operation is going on.

During the operation of bringing the strip ends into overlappingrelation, it is necessary to remove the gauge member 21 against whichthe ends of the strip are positioned when they are rst placed on theblocks 22 and 23. The member 21 is constructed in the form of a lever,as shown in Fig. 9,.its lower end being pivoted on a pin ||2 carried bythe upright frame 2| and its upper end being bent transversely as shownat 21a so that the vertical ilange 21brforming its extremity may projectinto a position between the blocks 22 and 23 to be engaged by the endsof the strip. The shoulders 21c at the inner end of the flange 21h,shown in Figs. 9 and 12, serve to position the strip ends laterally sothat they will line up 4properly with the recess 29B in the lowerforging die. To insure this result, the stop lever 21 is provided, asshown in Fig. 9, with a set screw 21d which engages a plate ||4 carriedby the frame member 2|e when the lever is in its forward position andwhich may be adjusted to locate the shoulders 21c properly. A coilspring m extending between this lever and a stationary part of themachine serves normally to move the Ylever to a position Where it willact as a gauge I2 is provided at oneend with a lever I5 which extendsupwardly, as shown in Figs. 1 and 6, with its rounded end ||5a extendinginto the recess of a cam ||8 which is secured on the inner end of theshaft by which the block 23 is moved through its oscillatory path. Thecam 8 has a recess ||6a to receive the extremity H* of the lever arm andthis .recess has an inclined face I6b which is adapted to cooperate withthe part I l5"A at a predetermined point'during the rotation of theshaft |01 to rock the lever |I5 about its axis to the vposition shown,Ain Fig. 7 while at the same time retracting the gauge member 21 to theposition shown in Fig. 9.

After the overlapping ends of the strips have been welded, in the mannermore fully described hereinafter, the foot pedals 10 and 96 may bereleased by actuating the rack bars 13 and 99 so that the clampingmembers 24 and 25 will be released by the levers 82 and 81,respectively. The handle 88 may then be actuated to cause the cam 85 torelease the clamping member 25 from the action of the lever 'Il and thewelded strip may then be removed. Then, upon turning the handle |09 inthe appropriate direction, the block 23 may be restored to its normalposition shown inFig. 1 and during this operation the end of the lever||5 will again extend Ainto the cam recess ||8 and the gauge member 2lwill be permitted under the influence of the spring I3 to return to itsnormal position shown in Fig. 1.

- The welding dies 29 and 30 are carried by die,

blocks H19 and |20, respectivelyi which Aare mounted for verticalmovement in guideways 2 and 2 |d which are formed in the forward portionof the upright frame 2|, as illustrated particularly in Figs. 1 and 9.Each guideway is formed between the side plates 2| of the upright frameand they are eachbounded on their rear sides by transverse iianges orwebs 2| Awhich are formed integrally with the side frame members. ATheguideways are bounded along their forward sides by plates |2| which areattached to the side plates 2lb along their forward edges by socketstuds |22 .engaging threaded apertures in the side frame members. 'I'heplates |2| overlap the die blocks ns and izo and the innr edges of eachpair of plates are spaced apartto form a vertical slot through whichaccess may be had to the block mounted within the guideway.

'Ihe lower die block I9 is provided with a bore ||8l in which is mountedthe lower die 29, and the upper die block is provided at its lower endwith a similar axial bore |2|B in which is mounted the upper die 30.Each die is held in place by a socket set screw |24 engaging a threadedaperture extendingv through a boss in the front side of the die block.These set screws are accessible through the slots between the plates|2|, as shown in Fig. 1. In order to Asupport the dies l29 and 30independently or the set screws |24. the die blocks ||9 and |20 areprovided with internal supporting pins |25 which extend throughapertures in the die blocks with their ends |25'l seating against thedies. Each pin |25 has a threaded portion I2 5b which engages a threadedpart of the aperture of the die block in which it is mounted and eachlpin is provided at its outer end with a hexagonal recess |25c adaptedto be engaged by a socket wrench for eii'ecting the adjustment of thepin to correspond with the position of the die, 29 or 30,- which isengaged thereby. Each pinY |25 is engaged at its outer threaded end by alock nut |26 which holds itin adiusted position. By this arrangement thedies .v 5 may be secured in the desired position to coact with stripmaterial of various gauges and after the dies have been adjustedthe pins|25 may be adjusted in the die blocks to give adequate support to thedies during the welding operation. Of

course, this arrangement also permits the dies 29 and 30 to beinterchanged with other-dies of different lengths and having projectionsand recesses of different widths and depths to accommodate strips ofvarious widths and gauges.

The lower die block I9 is provided at its lower end and onopposite sideswith a pair of rectangular notches ||9b and the upper die block |20 issimilarly provided with opposite rectangular notches |20". These notchesare engaged by the rounded extremities |2`|8L of the bifurcated forwardarms oi' operating levers |21 which are pivotally mounted on shafts |28vsecured in bearings carried by the side frame members 2|.

These levers extend rearwardly between theV side frame members |2|b andare pivotally connected by pins |29 with actuating links |30 which, whenthe dies 29 and 30 are in engagement with each other, extendsubstantially in vertical directions asshown in Fig. 9. The'links |30extend between the side ilanges |3| of a block |3| which is formed onthe end of a piston rod |32 and the links are pivotally connected to'this head |3| by means of a pin |33. The piston rod |32 extends throughan aperture formed in the end wall 2|t of the upright frame, as shown inFig. l9, and through an aperture formed in the head |35* of a cylinder|35. A piston |36 is mounted in this cylinder for actuation bycompressed air admitted thereto as hereinafter described. A-stuiiingvbox |35h is formed in the head |35n around the piston rod |32l and itis filled with packing material |731 adapted to be compressed by apacking gland |38 surrounding the piston rod and entering the otherportion of the stuillng box with its annular iiange secured to the head|35. 2

As shown in Fig. 5, the cylinder |35 is provided at its other end with adetachable head |39 and by longitudinal bolts |40 engaged at their rearthreaded ends by the nuts 14| andwashers |42. Compressed air or othermedium under pressure is adapted to be admitted to the forward end ofthe cylinder |35 through a pipe |43 which is mounted inthe head |35l tocommunicate with a port |359 leading to the forward end of the chamberof the cylinder. Another supply pipe |44, for compressed air or thellke,has its discharge end mounted in the rear cylinder head |39 tocommunicate with a port |39 formed therein so that compressed air may beadmitted to the rear end of the cylinder when desired. The admission ofcompressed air or other operating medium to the'opposite` ends of thecylinder |35 through the pipes |43 and |44 is controlled by an automaticvalve mechanism |45 to which.

the compressed air or other` medium is supplied through a pipe |48. Withthe foregoing arrangement, it will be apparent that upon admission ofcompressed air or other fluid to the rear end of fthe cylinder |35through the pipe |44, the piston |30 will be forced to the positionshown in Fig. 9,

thus actuating the toggle'm'echanism made up of z the links |30 and thelevers |21 to effect the movement of the dies 29 and 30 to the forgingor welding position where they contact with each other. Upon admissionof compressed air or lother medium through the pipe |43 to the forwardend of the cylinder |35, the piston |38 is moved in the oppositedirection and the toggle .rod plungers |56 and |51 which are adapted tobe actuated by the pivotal movement of the lef ver to control theadmission of compressed air to the pipes |43 and |44,'respectively. Acoil spring |58 connects the end of the lever |52 which is opposite thelink to the base of the controlling valve and this spring tends normallyto actuate the lever |52 in such a manner that compressed air isadmitted through the pipe |43 to the forward end of the cylinder |35 sothat thev piston |36 is actuated to operate the toggle mechanism andeifect the separation of the welding dies 26 and 30.

In order to obtain the uniformity in the welds or joints which areformed by the operation of the apparatus of the present invention and toinsure adequate strength in the joints, it is essential that the lappedends of the strips be heated to a predetermined extent before theforging operation takes place. Owing to variations in voltage and tovariations in the resistance of the overlapping portions of themetal'strips which are included in the welding circuit, it is notpossible to bring about a uniform and predetermined heating of theoverlapping strip ends merely by passing an electric current through thestrip ends for a predetermined period of time, and provision hastherefore been made for causing a predetermined or xed amount ofelectrical energy to pass through the lapped portions of the metalstrips preliminary to each forging operation. In Fig. 1'1, one circuitarrangement by which this result may be accomplished is somewhatdiagrammatically illustrated.

As there shown, the winding of the solenoid |50 is shown as beingconnected across the line between two supply conductors or line wires|60 and l6| leading from a suitable source of electrical energy. Thereis also connected between the supply conductors |60 and |6| a weldingtransformer |62, the secondary windings of which are |66d which areactuated by the solenoid |66 previously described. From the switchcontacts |66d, a conductor leads to a movable contact |69 which isadapted to be connected at a desired intermediate point of the secondarywinding of the control transformer |63. The terminals of this secondarywinding of the transformer l 63 are directly connected to the terminalsof a rectifying tube |10 which also has an intermediate terminalconnected through a conductor 1| with an adjustable rheostat |12. Themovable contact |12 of this rheostat is connected to a fixed condenser|13 having its other terminal connected to the conductor which leadsfrom the neon tube |66 to the contacts |66d. Thus, the fixed condenser|13 is connected in parallel with the solenoid |61 and the neon tube|68. This control circuit connected ied by regulating the charge of thefixed conconnected through the previously described barA Y conductors 44to the overlapping strip ends 26'l and 26h. The primary winding of thistransformer, in addition to being connected to the supply conductors and|6l, is included in circuit with the primary winding of a controltransformer |63 and also in series with the contacts |64c of a solenoid|64. The solenoid |64 is also connected between the supply conductors|60 and |6| and in series with a push/ button switch and the contacts|66c of an ther solenoid |66. This solenoid |66 is connected between thesupply conductors |60 and |6| and it is in series with contacts |61=controlled'by a, solenoid |61. Other contacts |61d are also controlledby the solenoid |61 and are connected in series with the weldingsolenoid v|50 previously described.

. The solenoid |61 has its winding included in a control circuit adaptedto be energized by the secondary winding of the control transformer |63with which it is connected; The winding of the solenoid |61 is connectedin series with a through the neon tube |66 and the solenoid |61,Y

leased and the circuit will be continued around' the switch throughaholding circuit including a condenser |14. When the solenoid 64 isenergized, it closes the normally open contacts |64c and thus energizesthe primary winding of the welding transformer |62 and also the primarywinding of the control transformer |63. The in duced welding current inthe secondary winding of the transformer |62 then passes between thestrip ends 26* and 26b for a period which is determinedby the operationof the control circuit in which the solenoid I 61 is included.

The control transformer |63 being then energized by the closing of theswitch |642 a current -will flow in the control circuit and the fixedcondenser |13 will be charged at a rate depending upon the adjustment ofthe rheostat |12. The contacts |66i are normally closed and remainclosed during this charging operation. At a predetermined time,regulated by the gas filled rectifying tube |16, the condenser |13 willdischarge thereby causing the solenoid |61 to close the contacts |61eand |614. When this occurs, the solenoids |66 and |56 are energized sothat two operations immediately take place. First, the normally closedswitch contacts 66e are opened, thus opening the circuit of the solenoid|64 and thereby causing the opening of the switch contacts |64 so thatthe supply of current to the primary windings of the two transformers|62 and |63 is interrupted. Secondly, the solenoid |50, being energized,actuates the valve |41 to admit compressed air to the cylinder |66 sothat the toggle mechanism is immediately actuated to force the twowelding dies 2! and 36 toward each other with a welding pressure onopposite sides of the overlapped 'and heated strip ends. After a weldingoperation of the dies in this manner, the spring |66 restores the lever|62 toga position neon tube les and in series with switch contactswherein compressed air is admitted through the and in which theoperation of uniting the over` lapping strip ends is eiected by aforging operation at an ordinary forging temperature, as dis.

tinguished fromva pure welding operation taking place at a highertemperature in'lwhich the metal is in a molten condition. By conning theoverlapping strip ends during the forging operation so that the metalcannot now laterally, it is possible to produce a joint having the samewidth and thickness as the strip ends which are united and havingsubstantially the same strength. By ad- Justing the control circuit, itis possible to adapt the apparatus to the heating of lmetal strips ofvarious gauges and widths and tobring about the desired degree ofheating before the forging operation takes place. By adjusting thewelding forging said overlapping ends while retainingV blocks and thedies, the apparatus may be employed with various gauges and widths ofmetal strips and there will be a certainty o f producing on eachoperation a joint having a predetermined size and strength.

Although one 'form of the invention has been 'y shown and described byway of illustration, it will be understood that it may be constructed'in Vvarious other embodiments coming within the scope ofthe appendedclaims.

We claim:

1. 'I'he method of uniting metal strips, which consists in placing theoppositely directed ends of the strips in overlapping relation insubstantially parallel planes, heating the overlapping ends throughouttheir width to a forging temperature. and then applying a forgingpressure to said ends Vtransversely to said planes while confining themetal of said overlapping ends against lateral flow beyond the initialwidth of said strips at the place of overlap.

2. The method of uniting metal strips, which consists in placing theoppositely directed ends of the strips in overlapping relation byplacing the strips -in alignment and effecting movement of one oi' themthrough an arcuate path until" it overlaps the other end, then heatingthe overlapping ends by passing an electric current therei through, andthen applying a forging pressure to said ends while restraining vthemetal of the overlapping ends against lateral now beyond the initialwidth of said strips.

3. The method of uniting metal strips, which consists in placing theoppositely directed ends ofthe strips in overlapping relation insubstantially parallel planes, heating the overlapping ends, and thenapplying a forging pressure to'said overlapping ends while restrainingthe metal of said ends against' lateral ow beyond the initial width ofsaid strips and permitting the longitufor heating the overlapping endportions of said strips throughout their widths to a forgingtemperature, the portions of said strips between said gripping meansbeing adapted to dissipate the heat developed in the overlappingportions, and means independent of said heating means for them in theposition in which they are heated.

5. The combination in apparatus of the class described, of means forholding two metal strips with their ends in substantial alignment, meansfor moving one of said holding means through an arcuate path to causeone strip end to overlap the other strip end with a wiping action, meansfor heating the overlapping ends by the passage of an electric currenttherethrough, and means for applying a forging pressure to theoverlapping heated ends.

6. The combination in apparatus of the class described, of means forholding two metal strips, means for moving one of said holdir'rgmeans,to

cause .the end of one strip to overlap the end of the other strip with awiping action, means for heating the overlapping ends of said strips,

a pair of forging dies, and means for actuatingl u said dies to forgethe overlapping heated lends of said strips, said dies having partsadapted to enclose said heated ends to prevent iloW of the metaltransversely to the longitudinal axes oi said strips when the forgingpressure is applied.

7. The combination in apparatus of the class described, of a pair ofclamping blocks, means for clamping metal strips on said blocks insubstantial alignment, a gauge for positioning the ends of said stripsin definite spaced relation, and means for moving one of said blocks tocause the ends of said strips to overlap and for dinal ilow of theheated metal at the place of v v overlap.

4. The combination in apparatus of the class described, of ,means forgripping the ends of two metal strips at points removed from theirextremities and holding portions of said ends in overlappingrelationship with their ends directed in opDOsite directions in parallelplanes, means simultaneously removing said gauge.

8. The combination in apparatus of the class described, of a pair ofblocks each adapted to support a metal strip, a gauge against which theends of said strips are adapted to be positioned, means for securingsaid strips on said blocks, means for effecting relative movement ofsaid blocks to cause the ends of said strips to overlap, and means forsimultaneously moving said gauge out of alignment with said strips 9.The combination in apparatus of the class described, of a pair of blockseach adapted to support a. metal strip, a gauge against which the endsof said strips are adapted to be positioned, means for securing saidstrips on said blocks, means for effecting relativemovement of saidblocks to c ause the ends of said strips to overlap, and means actuatedby thev operation of said last-named means for removing said gauge topermit said overlap.

10. The combination in apparatus of the class described, of a pair of'blocks, each adapted to support a, metal strip in substantial alignmentwith the strip on the other block, a gauge adapted to be engaged by theends of said strips, means for clamping said strips on said, blocks,means comprising an eccentric for moving one of said blocks through anarcuate path to cause the Aend of one strip to overlap the end of theother strip, and means actuated during the rotation of said eccentricfor withdrawing said gauge.

11. The combination in apparatus of the class described, of a pairv ofblocks, each adapted to support a metal strip in substantial alignmentwith the strip carried by the other block, a gauge adapted to. beengaged by the ends of said strips, means for clamping said strips onsaid blocks, means comprising an eccentric for moving one of said blocksthrough an Varcuate path to cause the end of one strip to overlap theend of the other strip, and a cam actuated during the rotation of saideccentric for causing the withdrawal of said gauge.

12. The combination in apparatus of the class described, of a pair ofblocks each adapted to support a metal strip, a pair of clamping memberseach adapted to engage a strip on one of said blocks, independentlyoperated means for securing each clamping member in its clampingposition, and separate manually operated means for holding one of saidclamping members in its clamping position preliminary to the operationof the securing means associated with that clamping member.

13. The combination in apparatus of the class described, of a pair ofblocks each adapted to suport a metal strip, a pair of clamping memberseach adapted to engage a strip on one of said blocks, independentlyoperated means for securing each clamping member in its clampingposition, separate manually operated means for holding one oi saidclamping members in its clamping position preliminary to the operationof the holding means associated with that clamping member, and meansactuated vafter said manually operated means has been operated to holdone of said strip ends for moving one of said blocks to bring the endsof said strips into overlapping relation.

14. The combination in apparatus of the class described, of a blockadapted to support a metal strip, a clamping member for securing saidstrip en said block, a manually operated lever for causing said clampingmemberwto hold said strip on said block, and vadditional foot operatedmechanism having a part adapted to engage said clamping member forholding said clamping member in engagement with said strip independentlyof said manually operated means.

15. The combination in apparatus of the class described, of means forholding a pair of strips with their ends overlapping, a pair of dieblocks movable transversely tosaid strip ends, Avvelding dies carriedby-said blocks, means for adjusting the positions of said dies in saidblocks, and

vmeans for eiecting relative movement of said blocks.

16. The combination in apparatus of the class described, of means forholding a pair of strips with their ends overlapping, a pair of die'blocks movable transversely to said strip ends, welding dies carried bysaid blocks, fluid pressure operated toggle mechanism adapted to effectrelative movement of said die blocks, means for heating the overlappingends of said strips, and means actuated after a predetermined heating ofsaid strip ends for actuating said duid pressure operated togglemechanism.

17. 'I'he combination in apparatus of the class described, of means forholding two metal strips with their oppositely'directed ends overlappingin parallel planes, means for heating said overlapping ends throughouttheir width, means for applying a forging pressure to usaid overlappingends while they are heated, and means for conning the metal of theoverlapping ends against flow transversely of said strips beyond theinitial width of said strips during the application of said pressure.

18. The combination in apparatus of the class described, of a pair ofWelding dies, one of said v dies having a groove adapted to receive astrip to be welded, the other of said dies having a projection adaptedto enter said groove, means for holding two strip ends with their endsoverlapping, means for heating the overlapping strip ends, and means foreffecting relative movement of said dies to enclose said overlappingends and apply a forging pressure thereto.

19. The combination in apparatus of the class described, of means forholding two metal strips with their ends in substantial alignment, meansfor moving one of said holding means to cause one strip end to overlapthe other, means for heating said overlapping strip ends, and means forapplying a forging pressure to the overlapped ends while said ends arein the position in which they are heated.

CHESTER M. MACCHESNEY. WILLIAM SCHROEDER.

